The Cafeteria Disease Clostridium perfringens is one of the most common food pathogens in the US and Europe. It is estimated to cause >10,000 cases of food poisoning in the US annually, although it is seldom reported. C. perfringens is found in meat, vegetables and grains. It is most commonly associated with food borne illness from meat and gravy. Why is C. perfringens such a robust pathogen? It is a Gram-positive, sporeforming, anaerobic bacteria that can tolerate low levels of oxygen. It is found in the intestinal tract of animals and humans and is also associated with soil, dust, insects and sewage. The spores survive the cooking process. It can take up to an hour boiling for one log reduction of spores present in a food. It has a wide growth range (50F to 125F) and high optimum growth temperature (110F). C. perfringens has the ability to double in 7 - 10 minutes in the optimum growth range. This can place C. perfringens at unacceptably high levels within an hour if food is mishandled. This organism can also remain at unusually high numbers in a food product for a long period of time. Once the contaminated food product is ingested, C. perfringens sporulates in the intestinal tract and produces an enterotoxin that causes severe stomach cramps and diarrhea (8-22 hr onset / symptoms last 12-18 hours). C. perfringens food poisoning is not often reported because it is over so quickly and it very seldom causes death. It is sometimes called the "Cafeteria Disease" due to the large number of reported outbreaks originating from foods served cafeteria style.
A case of C. perfringens food poisoning was reported in Ohio involving deli cooked corned beef for St. Patrick's Day. Around 1,400 lbs of corned beef were boiled for 3 hours. The meat and broth were allowed to cool at room temperature and then refrigerated. Cooking, cooling, and 4C storage of the 1,400 lbs were staged over 4 days prior to March 17th. The
deli removed the corned beef from the refrigerator, sliced the meat, then held it in a warmer at 120F while it was served at the party. After the celebration, 156 people came down with food poisoning. Not a good way to celebrate a festive holiday!
Where did the deli go wrong? The three main mistakes were 1) not rapidly cooling the cooked product in small portions so that the meat was quickly cooled below 40F, 2) not reheating the product to an internal temperature of 165F, and 3) not holding the reheated product at a serving temperature of greater than 140F. Proper cooling would have prevented C. perfringens growth, proper reheating would have inactivated any vegetative C. perfringens present after storage, and the proper serving temperature would have prevented growth during serving. Current methodology is found in the FDA-BAM. The method includes an enrichment procedure for the detection of low levels of C. perfringens (<10 cells per gram) and a plating procedure on selective media (Tryptose sulfite cycloserine agar) if higher levels are suspected. Complete biochemical confirmation is required to substantiate the presence of C. perfringens in a sample.
Ambiguity Propagating Defeasible Logic and theDepartment of Computer Science and Artificial Intelligence CenterAbstract. The most recent version of defeasible logic (Nute, 1997) is related tothe well-founded semantics by translating defeasible theories into normal logicprograms using a simple scheme proposed in (Brewka, 2001). It is found thatby introducing ambiguity propagation into this logic,
Siobhan’s Story Epilepsy and me To tell the full story of how I developed epilepsy, I have to go back to my childhood, as I was never in good health from then. I was born in Lisburn and shortly after I was released home to my parents, they realised something was wrong. I was brought to the RVH in Belfast where I had to undergo serious operations on my bladder and bowel, b